After watching this video from the security camera I assumed that Elisa was on drugs.

Autopsy reports however showed that no drugs were in her system.

The more you look at the Cecil Hotel the more that you see that this place could have a significant paranormal "shadow." The hotel is known to be the location of countless suicides and noted serial killers have stayed there. 

"The Hotel is known for several suicides and its criminal activity which includes three murders. Most notably, the hotel was the reported residence for serial killers Richard Ramirez in 1985 and Jack Unterweger in 1991. It is rumored to be one of the last places Elizabeth Short was seen before her murder in 1947."

So the question is if Elisa could have been tormented by spirits and driven to somehow climb into the water tank. Possibly she could even have been possessed by one of these phantoms. I have also heard the theory about alien abduction. Could Elisa have been using the elevator as some kind of portal? Perhaps she was communicating with something through the elevator buttons. Was it possible that the aliens beamed her back to the wrong spot and she ended up in the water tank?

Still another theory could be the possibility of a human tormentor. Was she speaking with someone just out of the camera's view? Could she have been fleeing a murderer and tried to hide in the water tank? Was she forced to enter the water tank? 

The most logical explanation would be a mental breakdown or some kind of psychotic episode, but that doesn't explain quite a few circumstances. To access the roof Elisa would have had to pass through a locked roof door that was secured with an alarm. The water tank that Elisa was found in wasn't easily accessible either I'd imagine that these water tanks have heavy covers that would need to be moved off. In fact after her death workers had to cut the tank open to get the body out. This was a small twenty three year old woman, was she strong enough to open the tank? What about the elevator, why did the door only close after she was gone?

So what do you thin is going on here? What do you think are the circumstances behind Elisa's death? Could it be Alien, Ghost, Crazy Killer or was she simply unstable mentally?